THE  SEPARATION  OF  COLUMBXUM 
AND  TANTALUM  FROM  FER- 
GUSONITE 


BY 


EMIL  CHARLES  NEMITZ 


THESIS 


FOR  THE 


DEGREE  OF  BACHELOR  OF  SCIENCE 

IN 

CHEMICAL  ENGINEERING 


COLLEGE  OF  LIBERAL  ARTS  AND  SCIENCES 


UNIVERSITY  OF  ILLINOIS 


1922 


\ 

N 34 

UNIVERSITY  OF  ILLINOIS 

Ma£_25j i92J3^_ 

THIS  IS  TO  CERTIFY  THAT  THE  THESIS  PREPARED  UNDER  MY  SUPERVISION  BY 

Emil  0.  Nemitz 

ENTITLED— _SEPARAT 1 ON  _ 0F_ _0 OLUMBIUM _ MD_  TANTALUM  

FERGUS ONI TE . 

IS  APPROVED  BY  ME  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR  THE 

degree  of _ _of _ jsnianoe _ 



Instructor  in  Charge 

Approved  Jl  __ 

HEAD  OF  DEPARTMENT  OF 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/separationofcoluOOnemi 


TABLE  OF  CONTENTS 


Page . 


I,  Introduction  1 

II.  Chemical  Characteristics  of  the  Rare 

Elements  in  the  Ore  2 

III.  Methods  for  Opening  the  Ore  6 

IV.  Experimental  Part  10 

V.  Data  14 

VI.  Discussion  of  Results  16 

VII.  References  17 


ACKNOWLEDGMENT . 

The  author  wishes  to  thank  Dr.  Rosalie  M.  Parr,  under 
whose  direction  this  work  was  carried  out,  for  her  helpful 
suggestions  and  encouragement. 

E.  C.  N. 


1. 


THE  SEPARATION  OF  COLUMBIUM  AND  TANTALUM 
FROM  FERGUSONITE. 

I . INTRODUCTION . 

Columbium  and  tantalum  are  always  associated  with  each 
other  in  nature.  They  usually  occur  as  oxides.  In  ferguson- 
ite, the  columbium  and  tantalum  oxides  are  found  in  combina- 
tion with  various  rare  earth  oxides.  The  general  formula  Is 
usually  written  H**  (Cb,Ta)04  , in  which  R stands  for  a metal 
of  the  rare  earth  series,  yttrium,  erbium,  and  cerium  are 
the  ones  generally  found. 

Fergusonite  is  found  in  various  parts  of  the  globe. 
There  are  deposits  in  South  Norway,  Australia,  Ceylon,  Mada- 
gascar, and  several  parts  of  the  United  States.  It  is  al- 
most always  found  on  or  between  large  flakes  of  biotite.  The 
freshly  mined  mineral  has  a velvet  black  color,  and  is  very 
shiny.  After  heating  the  color  changes  to  olive  green. 

The  mineral  used  in  connection  with  this  work  came  from 
Norway.  The  first  work  done  on  the  mineral  was  the  removal 
of  the  rare  earths.  The  ground  ore  was  treated  with  concen- 
trated hydrochloric  acid,  and  heated  on  a steam  bath  for  24 
hours.  From  time  to  time  concentrated  nitric  acid  was  added. 
At  the  end  of  24  hours,  the  mass  was  evaporated,  and  then 
heated  to  150°C  to  decompose  the  silicic  acid.  The  rare 
earths  were  extracted  with  water,  and  the  residuum  was  used 
for  the  following  work. 


, 


■ • 


2. 


II.  CHEMICAL  CHARACTERISTICS  OF  THE  RARE  ELEMENTS 

IN  THE  ORE. 

COLUMBIUM . 

Metallic  columbium  has  a light  gray  color  and  a bril- 
liant luster.  It  is  as  hard  as  wrought  iron,  and  is  mallea- 
ble and  ductile.  When  heated  in  the  air,  it  slowly  oxidizes 
to  Cb^O^  • The  metal  is  insoluble  in  hydrochloric,  nitric, 
or  sulphuric  acid,  but  is  attacked  by  hydrofluoric  acid  and 
by  fused  alkalies  at  a red  heat. 

Columbium  forms  three  oxides,  CbgCX,  , GbgO^  , and  CbgOg, 
the  latter  being  an  acid  anhydride.  CbgOg  is  a white  amor- 
phous powder  which  is  infusible,  and  becomes  cryatalline  when 
strongly  heated.  It  is  insoluble  in  the  mineral  acids,  ex- 
cept concentrated  sulphuric  acid,  in  which  it  is  very  slight- 
ly soluble,  and  hydrofluoric  acid  in  which  it  very  readily 
dissolves.  If  treated  with  concentrated  hydrochloric  acid, 
it  does  not  dissolve,  but  the  residue  is  soluble  in  water. 

By  fusion  with  an  excess  of  potassium  hydroxide  or  potassium 
carbonate,  the  potassium  hexacolumbate  (K^Cb^O^)  ls  obtained. 
This  compound  is  soluble  in  water.  If  a mineral  acid  is  add- 
ed to  the  solution  of  potassium  hexacolumbate,  and  it  is 
boiled,  columbic  acid  (HgCb^O^g)  is  precipitated.  Tartaric 
acid  prevents  this  precipitation.  Columbic  acid  is  a white 
amorphous  powder,  slightly  soluble  in  hot  concentrated  sul- 
phuric acid,  and  very  easily  soluble  in  hydrofluoric  acid. 


' 


3. 


If  potassium  fluoride  is  added  to  the  hydrofluoric  acid  solu- 
tion, potassium  f luocolumbate  (KgCbF^ ) is  formed  which  is  sol- 
uble in  12.5  partB  of  water.  If  a little  free  hydrofluoric 
acid  is  present,  the  oxyfluoride  (K  GbOF  ) is  formed,  which  is 

& O 

still  more  soluble.  Zinc  added  to  a solution  of  the  hexacol- 

* 

umbate  produces  a fine  blue  color.  The  presence  of  a little 
hydrofluoric  acid  prevents  this  reaction.  With  potassium  fer- 
rocyanide  a green  precipitate  is  obtained. 

TANTALUM. 

Metallic  tantalum  is  silver  white  in  color,  and  as  hard 
as  the  best  steels.  It  can  be  rolled,  hammered,  and  drawn  in- 
to fine  wire.  Its  melting  point  is  about  2250°C.  It  is  not 
attacked  by  aqua  regia  nor  by  any  single  acid  except  hydro- 
fluoric acid.  It  is  also  attacked  by  fused  alkalies. 

The  properties  of  the  compounds  of  tantalum  are  very 
much  the  same  as  those  of  columbium.  Tantalum  forms  the  two 
oxides  TagO^  and  TagO^,  which  react  the  same  as  Cbg04  and 
CbgOg.  The  tantalates  are  also  similar  to  the  columbates, 
except  that  alkali  tantalates  are  precipitated  by  a current 
of  COg^-  while  the  columbates  are  not.  Tantalic  acid  is  sol- 
uble in  hydrofluoric  acid.  If  however  potassium  fluoride  is 
added,  colorless  crystals  of  potassium  f luotantalate  (KgTaFr, ) 
are  precipitated,  whion  are  soluble  in  about  200  parts  of  wa- 
ter. If  the  solution  of  the  double  fluoride  is  boiled,  a 
very  insoluble  oxyfluoride  is  precipitated  as  a white  powder. 
Zinc  added  to  a solution  of  the  hexatantalate  produces  no  col- 


. 


■ 


> 


4. 

or.  With  potassium  ferrocyanide  a yellow  precipitate  is  formed. 

TITANIUM. 

The  metal  has  a brilliant  white  color,  and  is  very  brit- 
tle and  hard.  When  heated  in  the  air,  it  unites  with  oxygen  to 
form  TiOg.  Metallic  titanium  is  soluble  in  hydrochloric,  nitric, 
sulphuric,  hydrofluoric,  and  acetic  acids.  Its  melting  point 
is  1794°C. 

The  dioxide  is  a white  amorphous  powder,  insoluble  in 
insoluble  in  water,  hydrochloric  or  nitric  acid,  and  is  dif- 
ficultly soluble  in  sulphuric  acid.  It  is  rendered  soluble 
by  fusion  with  a bisulphate. 

If  an  alkali  is  added  to  a hydrochloric  acid  solution 
of  a titanium  salt,  orthotitanic  acid  is  precipitated,  which 
is  readily  soluble  in  dilute  acids.  On  long  standing,  it 
gradually  changes  to  the  metatitanic  acid  (ELTiO„),  which  up- 
on  ignition  is  converted  to  the  dioxide. 

Fusion  of  the  dioxide  with  sodium  carbonate  produces 
the  three  soluble  titanates,  Na2Ti205,  Na2Ti307,  and  Na^TigOg. 
Hydrogen  peroxide  reacts  with  the  sulphuric  acid  solution  of 
the  dioxide  to  form  the  trioxide  (Ti03),  which  gives  an  in- 
tense orange-brown  color  to  the  solution. 

When  metatitanic  acid  is  treated  with  hydrofluoric  a- 

cid,  the  f luotitanate  (H0TiF. ) is  formed,  which  is  not  vol- 

<3  o 

atilized  like  SiOg  by  evaporation  of  the  hydrofluoric  acid 
solution  in  the  presence  of  sulphuric  acid.  It  is  volatile 
however  if  the  sulphuric  acid  is  omitted.  By  the  addition 


■ 


5 


of  potassium  fluoride  to  HgTiFg,  KgTiFg  is  formed  which  is 
soluble  in  96  parts  of  water. 

GERMANIUM . 

Germanium  is  a grayish-white  metal  with  a fine  luster. 
It  is  soluble  in  sulphuric  acid,  nitric  acid,  and  aqua  regia, 
but  not  in  hydrochloric  acid.  The  compounds  are  found  in  two 
forms  of  oxidation,  the  higher  form  being  the  more  stable. 
Germanium  resembles  tin  in  the  formation  of  two  sulphides, 
GeS,  and  GeSg,  both  of  which  are  soluble  in  yellow  ammonium 
sulphide.  GeSg  is  a whits  powder  slightly  soluble  in  water, 
but  insoluble  in  concentrated  hydrochloric  acid.  GeS  is  red- 
dish-brown and  is  slightly  soluble  in  water. 

The  tetra-chloride  is  a liquid  which  fumes  in  damp  air. 
Its  boiling  point  is  86°C.  It  decomposes  in  water,  and  forms 
the  dioxide,  a white  difficultly  fusible  powder,  which  is  sol 
uble  in  both  acids  and  alkalies.  If  the  dioxide  is  dissolved 
in  hydrofluoric  acid,  and  potassium  ohloride  added,  gelati- 
nous K0GeF  is  precipitated. 

d 6 


. 


. 


6. 


III.  METHODS  FOR  OPENING  THE  ORE. 

In  the  literature  the  following  methods  for  opening  the 
ore  are  mentioned. 

1.  Fusion  with  potassium  acid  fluoride. 

2.  Fusion  with  potassium  hydroxide. 

3.  Fusion  with  fused  potassium  acid  sulphate. 

4.  Fusion  with  potassium  carbonate. 

5.  Fusion  with  potassium  carbonate  and  borax. 

6 . Fusion  with  sodium  carbonate . 

7.  Fusion  with  sodium  peroxide. 

8.  Treat  mineral  with  finely  ground  carbon  in  an  elec- 

tric furnace. 

9.  Treat  mineral  with  dry  chlorine  at  a red  heat. 

POTASSIUM  ACID  FLUORIDE  FUSION.'^ * 

The  mineral  Is  fused  with  three  parts  of  potassium  fluo- 
ride, and  the  melt  pulverized  and  dissolved  in  hot  water.  Dil- 
ute hydrochloric  acid  is  added  to  precipitate  the  columbic  and 
tantalic  acids.  The  acids  are  thoroughly  washed  with  water, 
dissolved  in  hydrofluoric  acid,  and  potassium  carbonate  add- 
ed until  a precipitate  is  formed.  The  tantalum  precipitates 
as  the  potassium  f luotantalate,  and  the  coiumbium  as  the  oxy- 
f luoride . 

POTASSIUM  HYDROXIDE  FUSION. 

This  fusion  is  recommended  by  Simpson3  for  high-grade 


> 


. 


■ 

. 


7 


coiumbiura  and  tantalum  minerals  that  are  substantially  free 
from  titanium.  The  finely  ground  mineral  is  fused  with  six 
times  its  weight  of  potassium  hydroxide  in  a nickel  or  sil- 
ver crucible.  The  crucible  snould  be  supported  in  a perfor- 
ated piece  of  asbestos  board,  so  that  only  the  lower  part  of 
the  crucible  is  heated.  In  this  way  creeping  is  prevented. 

The  heat  is  applied  slowly  at  first,  and  gradually  increased 
to  a dull  red  heat.  It  is  kept  at  this  temperature  for  one 
half  hour  or  more.  The  soluble  part  of  the  fused  mass  is 
then  dissolved  in  water,  and  filtered  from  the  insoluble  part. 
A mineral  acid  is  then  added,  and  the  solution  boiled  for  20 
minutes  to  precipitate  the  earth  acids.  The  probable  impu- 
rities are  tin,  tungsten,  silica,  and  titanium. 

The  tin  ana  tungsten  are  removed  by  digesting  the 
precipitate  with  yellow  ammonium  sulphide.  The  silica  is 
volatilized  with  hydrofluoric  acid  and  sulphuric  acid.  The 
titanium  may  be  removed  by  either  fusing  with  potassium  acid 
sulphate,  or  by  treating  the  mixed  acids  with  ammonium  sali- 

4 

cyiate.  The  bisulphate  fusion  for  the  removal  of  titanium 
is  in  all  respects  the  same  as  the  bisulphate  fusion  for  the 
opening  of  an  ore.  The  best  separation  is  with  ammonium  sa- 
licylate. The  mixed  acids  are  treated  witn  an  excess  of  am- 
monium salicylate,  refluxed  for  three  or  four  hours,  and  fil- 
tered hot.  The  titanium  salicylate  is  soluble  and  is  there- 
fore found  in  the  filtrate,  while  the  columbium  and  tantalum 
salicylates  are  insoluble. 

POTASSIUM  ACID  SULPHATE  FUSION.5* 

The  finely  powdered  mineral  is  mixed  with  6-10  times  its 


8. 


weight  of  fused  potassium  acid  sulphate.  It  is  gently  heated 
at  first,  and  then  submitted  to  a strong  heat  until  no  dark 
particles  of  undecomposed  mineral  are  visible.  The  melt  is 
then  extracted  with  a large  quantity  of  boiling  water  con- 
taining a little  dilute  hydrochloric  acid.  The  impurities 
are  removed  by  the  same  method  as  in  the  potassium  hydroxide 
fusion. 

The  bisulphate  method  is  usually  used  on  the  lower 
grade  ores  or  those  high  in  titanium.  The  results  obtained 
by  this  method  are  a little  low,  because  it  is  impossible  to 
precipitate  the  earth  acids  completely.  The  decomposition 
also  is  very  slow,  often  taking  more  than  five  hours,  while 
many  finely  powdered  minerals  are  decomposed  by  fusing  one 
half  hour  with  potassium  hydroxide. 

FUSION  WITH  POTASSIUM  CARBONATE  AND  FUSION 
WITH  POTASSIUM  CARBONATE  AND  BORAX. 

These  fusions  are  in  ail  respects  the  same  as  the  po- 
tassium hydroxide,  but  they  are  not  as  convenient,  because 
the  carbonate  is  much  less  fusible  than  the  hydroxide. 

FUSIONS  WITH  SODIUM  CARBONATE 
AND  SODIUM  PEROXIDE. 

Fusion  with  sodium  carbonate  is  not  as  satisfactory  as 
with  potassium  carbonate,  because  of  the  greater  solubility 
of  the  potassium  salts  of  the  earth  acids. 

The  fusion  witn  sodium  peroxide  is  a very  rapid  method. 


■ 


. 


9. 


SPECIAL  TREATMENT  FOR  IMPURITIES. 

On  account  of  the  difficulties  encountered  in  purifying 
the  earth  acids,  Schoeller  and  Powell6recommend  the  removal  of 
as  many  impurities  as  possible  before  precipitating  the  earth 
acids.  Therefore  instead  of  leaching  the  fused  mass  with  wa- 
ter, they  suggest  using  a concentrated  solution  of  tartaric 
acid  in  water.  Tartaric  acid  prevents  the  precipitation  of 
the  earth  acids  by  the  addition  of  ammonia,  ammonium  sulphide, 
or  by  boiling.  After  the  fused  mass  has  been  leached,  the 
filtrate  is  saturated  with  hydrogen  sulphide  which  removes  tin, 
antimony,  and  any  other  second  group  metals  that  may  be  present. 
The  precipitate  is  filtered  off,  and  the  filtrate  digested  with 
ammonia  and  ammonium  sulphide.  This  removes  the  iron,  uranium, 
and  some  of  the  manganese,  if  manganese  is  present. 

The  operation  so  far  eliminates  such  troublesome  impu- 
rities as  iron,  silica,  tin,  and  antimony,  while  the  oolumbiura 
and  tantalum  are  still  in  solution.  A method  for  removing  the 
titanium  before  preoipitation  has  not  yet  been  found. 


. 


10 


IV.  EXPERIMENTAL  PART. 

POTASSIUM  HYDROXIDE  FUSION. 

The  raw  material  obtained  by  treating  fergusonite  with 
aqua  regia,  and  leaohing  out  the  rare  earths  with  water,  oon- 
tained  a large  amount  of  moisture,  and  had  to  be  dried  at  104° 
to  110°C  for  one  hour  before  the  fusion  oould  be  made.  The 
potassium  hydroxide  was  first  placed  in  a large  fire-clay  cru- 
cible and  gently  heated  in  a gas  furnace . When  it  was  in  a 
state  of  quiet  fusion,  the  finely  ground  residuum  was  added, 
and  the  temperature  gradually  increased  until  a dull  red  heat 
was  obtained.  It  was  kept  at  this  temperature  for  one  and 
one  half  hours,  and  then  poured  into  an  iron  mold.  The  melt 
had  a color  very  similar  to  the  green  ferrous  salts,  and  was 
very  hygroscopic.  After  remaining  in  contact  with  the  air  for 
a while,  the  color  turned  brown.  This  was  probably  due  to  the 
oxidation  of  the  ferrous  salts  to  ferric  salts. 

The  soluble  part  of  the  melt  was  extracted  with  a large 
quantity  of  water,  and  the  insoluble  portion  filtered  off.  The 
earth  acids  were  precipitated  by  the  addition  of  sulphuric  a- 
cid,  and  then  boiling  the  solution  for  20  minutes.  Should  the 
solution  be  made  too  acid,  the  precipitate  would  be  very  fine- 
ly divided,  and  very  hard  to  filter.  By  neutralizing  most  of 
the  excess  acid  with  ammonia,  and  by  boiling,  this  inconven- 
ience can  be  avoided. 

REMOVAL  OF  TITANIUM. 

After  titanium  was  found  to  be  present,  it  was  decided 


' 


. 


. 


- 


11. 


that  the  ammonium  salicylate  method  be  used  to  remove  it.  The 
mixed  acids  were  treated  with  concentrated  nitric  acid,  and  a 
neutral  solution  of  ammonium  salicylate  added.  A large  excess 
of  this  reagent  should  be  used.  A curdy  mass,  light  yellow  in 
color  was  formed.  This  was  then  refluxed  with  a large  quanti- 
ty of  water  for  four  hours,  and  filtered  hot.  The  titanium 
formed  a compound  which  was  soluble  in  hot  water,  while  the 
columbium  and  tantalum  compounds  were  not  soluble  in  hot  water. 

TREATMENT  OF  RESIDUUM  FOR  GERMANIUM. 

The  original  material  (f ergusonite ) had  germanium  pre- 
sent, and  because  of  the  value  of  this  element,  it  was  deci- 
ded to  attempt  to  extract  it  from  the  residuum  before  treat- 
ing it  for  columbium  and  tantalum,  xhe  simplest  way  of  ob- 
taining the  germanium  seemed  to  be  by  the  distillation  of  the 
tetra-chloride  in  an  atmosphere  of  chlorine.  At  first  a dry 
method  was  tried.  The  raw  material  was  placed  in  a hard  glass 
combustion  tube,  which  was  placed  in  a combustion  furnace  and 
heated  to  a temperature  of  150°C.  During  the  heating,  a slow 
current  of  chlorine  was  passed  thru  the  tube.  The  distillate 
was  caught  in  water,  where  the  germanium  tetra-chloride  would 
be  hydrolized,  and  germanium  dioxide  would  be  precipitated. 
However  no  precipitate  formed. 

It  was  then  decided  to  try  a wet  method  that  was  used  in 
the  extraction  of  germanium  from  zinc  residues.  The  material 
was  treated  with  concentrated  hydrochloric  acid,  and  the  hydro- 
chloric acid  distilled  in  an  atmosphere  of  chlorine.  The  ger- 
manium would  be  converted  to  the  tetra-chloride,  which  would 


12 


distill  over  with  the  hydrochloric  acid. 

The  apparatus  consisted  of  a one  liter  round-bottom  Py- 
rex  distilling  flask  supported  on  an  asbestos  collar  10  cm. 
high,  which  rested  on  a piece  of  transits.  A 2-hole  rubber 
stopper  was  placed  in  the  neck  of  the  flask,  the  one  opening 
for  a separatory  funnel  to  introduce  the  hydrochloric  acid, 
the  second  opening  for  a glass  tube  extending  nearly  to  the 
bottom  of  the  flask,  thru  which  the  chlorine  was  introduced. 

A Liebig  condenser  was  attached  to  the  arm  of  the  distilling 
flask.  A bent  glass  tube  was  attached  to  the  farther  end  of 
the  condenser.  This  tube  reached  nearly  to  the  bottom  of  a 
half  liter  bottle  partly  filled  with  water,  which  served  as 
a receiver.  The  receiver  was  surrounded  with  cracked  ice. 

The  heat  was  applied  with  a large  Meker  burner.  The  distil- 
lation was  continued  until  nearly  all  of  the  hydrochloric  a- 
oid  was  distilled  over,  but  no  preoipitate  formed  in  the  re- 
ceiver. 

Failure  to  find  any  germanium  seemed  to  indicate  that 
the  germanium  was  lost  when  the  fergusonite  was  treated  with 
aqua  regia  and  then  heated  to  150°C  to  decompose  the  silicic 
acid. 

EXTRACTION  OF  COLUMBIUM  AND  TANTALUM. 

After  the  material  had  been  treated  with  concentrated 
hydrochloric  acid,  it  was  possible  to  dissolve  out  the  oolum- 
bium  and  tantalum  with  water,  and  a fusion  of  the  residue  was 
not  necessary.  To  precipitate  the  columbium  and  tantalum,  it 
was  only  necessary  to  boil  the  solution.  When  obtained  by  this 


■ 


' 


13. 


method,  the  columbium  and  tantalum  are  free  from  silica,  but 
contain  a great  deal  of  iron  and  titanium.  It  was  attempted 
to  remove  the  iron  by  washing  with  dilute  hydrochloric  acid, 
but  it  was  not  possible  to  get  rid  of  the  traces  by  this  meth- 
od. 

PYROSULPHATE  FUSION. 

The  residuum  was  fused  with  six  times  its  weight  of 
fused  sodium  acid  sulphate  in  a large  fire-clay  crucible. 

The  heat  was  applied  gently  at  first,  and  gradually  increased 
to  a dull  red  heat,  and  kept  at  that  temperature  for  two  hours. 
The  melt  had  a light  yellow  color.  At  this  point  however, 
instead  of  extracting  the  columbium  and  tantalum  with  water, 
a tartaric  acid  solution  was  used,  and  the  procedure  outlined 
by  Schoeller  and  Powell  was  followed.  In  this  way  all  of  the 
impurities  except  titanium  were  removed. 


' 


" 


14 


V.  DATA. 

MOISTURE  CONTENT. 

Weight  of  moist  residuum 
Weight  of  residuum  after  drying 
Weight  of  moisture  driven  off 

POTASSIUM  HYDROXIDE  FUSION. 

Weight  of  dried  residuum 
Weight  of  potassium  hydroxide 
Weight  of  impure  mixed  acids 

REMOVAL  OF  TITANIUM  WITH 
AMMONIUM  SALICYLATE. 

Weight  of  mixed  acids 
Weight  of  salioylio  acid 
Weight  of  mixed  acids  remaining 
Apparent  weight  of  TiOg 

PYROSULPHATE  FUSION. 

Weight  of  mineral  used 

Weight  of  sodium  pyrosulphate  used 

Weight  of  mixed  acids  obtained 


110  gr. 
95  gr. 
15  gr. 


95  gr. 
550  gr. 
80  gr. 


42  gr. 

25  gr. 
38.5  gr. 
1.5  gr. 


100  gr, 
600  gr. 
12  gr. 


■ 


15 


TREATMENT  OF  MINERAL  WITH  HOI  AND  Clg. 


I 

II 

Weight 

of 

mineral  used 

250.0  gr. 

250.0  gr. 

volume 

of 

HC1  added 

300.0  cc. 

300.0  cc. 

Weight  of  GeOg  obtained  — _ 

Weight  of  impure  mixed  aside.  75.1  gr.  83.7  gr. 


. ■_ 


16 


DISCUSSION  OF  RESULTS. 

In  the  potassium  hydroxide  fusion,  the  weight  of  the 
mixed  oxides  was  high  due  to  the  silica  present.  This  fu- 
sion was  made  in  a fire-clay  crucible,  so  the  amount  of  si- 
lica dissolved  by  the  potassium  hydroxide  was  very  high.  By 
using  a graphite  crucible,  however,  this  oould  be  avoided. 

By  this  method  no  iron  was  present  in  the  mixed  acids. 

By  using  concentrated  hydrochloric  acid,  the  mixed  a- 
cids  obtained  were  free  from  silica,  but  contained  a great 
deal  of  iron  which  could  not  be  completely  washed  out  with 
dilute  hydrochloric  acid.  This  method  is  a very  good  one, 
if  the  mineral  contains  germanium,  and  by  using  tartaric  a- 
oid  to  dissolve  the  columbium  and  tantalum  instead  of  water, 
and  removing  the  impurities  according  to  Schoeller  and  Po- 
well’s method,  this  difficulty  of  removing  the  iron  could 
be  overcome. 

In  the  pyrosulphate  fusion,  all  of  the  impurities, ex- 
cept titanium, were  removed  according  to  Schoeller  and  Powell’s 
method  before  the  acids  were  precipitated.  The  weight  of  the 
mixed  acids,  however,  was  low,  because  it  was  impossible  to 
precipitate  the  acids  completely  after  tartaric  acid  was  used. 
The  solution  in  this  case  would  have  to  be  evaporated  and  the 
tartaric  acid  ignited. 


■ 


. 


17. 


VII.  REFERENCES . 

1*. Weiss  and  Landecker.  Zeit.  Anorg.  Chem.  64,  65.  (1909). 

2.  Browning’s  Introduction  to  the  Rarer  Elements.  Page  119. 

3.  Simpson.  Chem.  News.  99,  243.  (1909). 

4.  Dittrich  and  jfreund.  Zeit.  Anorg.  Chem.  56  , 344.  (1908). 

5.  Schoeller  and  Powell’s  Analysis  of  Minerals  and  Ores 

of  the  Rare  Elements.  Page  139. 

6.  Schoeller  and  Powell.  J.C.S.  119,  1927.  (1921). 

7.  Dennish  and  Papish.  J.A.C.S.  43,  2131.  (1921). 


